Telephone-transmitter



(No Model.)

W. BURNLEY.

TELEPHONE TRANSMITTER No. 353,536. Patented Nov. 30, 1886.

nmlinm UNrTRo STATES PATENT OFFICE.

WILLIAM RURNLRY, or NORTH EAST, PENNSYLVANIA, ASSIGNOR or TWo THIRDS TO CHARLES A. nIronoooK, OF SAME PLACE, AND LEWIS F. WATsoN, on WARREN, PENNSYLVANIA.

TELEPHONE-TRANSMITTER.

SPECIFICATION forming part of Letters Patent No. 353,536, dated November 30, 1886.

Application filed August 12, 1886. Serial No. 210,693.

(No model.) Patented in England September 15, 1885, N0.10,'I50, and in France September 15, 1885, No. 171,195.

To coZZ whom it may concern:

Be it known that 1, WILLIAM BURNLRY, a citizen of the United States, residing at North East, in the county of Erie and State of Pennsylvania, have invented new and useful improvements in Telephone Transmitters, of which the following is a specification.

The present invention relates to that class of telephonic transmitters in which a tensionregulator for the electric current is set into action by sound-waves impinging against a diaphragm or vibrating body.

The object of the invention is to provide a simple and effective arrangement of devices, whereby the rise and fall of the electric tension or the changes in the electric current required to reproduce speech is effected by means of an electrode sliding freely on an in clined plane or table and cooperating with zofan electrode carried by a diaphragm. The

inclined plane or table is pivoted to the frame or holder which carries the diaphragm, and is provided with means for changing its inclination to vary the contact-pressure between the electrode sliding thereon and the diaphragmelectrode. The adjusting device is a screw which impinges against and Supports the platform in position, as will be hereinafter more fully described, and then set forth in the claims.

In the drawings, Figure l is a vertical section of a telephonic transmitter embodying my improvements. Fig. 2 is a horizontal section through the line 00 00 of Fig. 1. Fig. 3 is a detail view of the pivoted platform or adjustable frame for the sliding electrode.

The reference numerall denotes the wooden ring or frame for the support of the diaphragm 2. In the inner surface of this ring, which is disposed vertically, are formed opposite slots 1, having a downward inclination and opening at the back of the ring. These slots receive the pivots or trunnions 4 of the inclined plane or platform 3,showni11 Fig.3. This plane, which is composed of brass or a suitable conducting metal, is also provided with small lugs 5, adapted to hold the electrode 6 from lateral displacement.

This electrode 6 is free to slide on the inclined plane; and it consists of a carbon pencil to which is fastened,by glue or in any other suitable manner, apiece of glass, metal, wood, or other material, 7, which serves to weight the electrode and to preserve the contact-surface between it and another electrode, 8, carried by the diaphragm 2. The electrode 8 is also a carbon pencil of the same length as the pencil forming the electrode 6, and it is seen red, by glue or otherwise, to a knob or projection, 9, on the rear of the diaphragm. An electric-circuit wire, 10, extends from the electrode 8, and another circuit-wire, 11, runs from the electrode 6 or from the apex ofthe inclined plane 8. \Vhen the pivots or trunnions of the latter are inserted in the slots 1 of the frame 1,the plane is free to turn, and can be set at any angle required above a horizontal plane. A vertical set-screw, 12, is tapped through a lug, 13, on the ring 1, and its upper end impinges against and supports the plane 3 in its position. By adjusting this screw up or down the inclination of the plane may be varied to any desired degree within the limits of its movement. By such change of inclination of the plane 3 it follows that the degree of contact between the loose sliding electrode and the one carried by the diaphragm may be varied to any desired degree-for example, by causing the plane to approach the vertical the contact will be increased by the gravity of the loose electrode, which is a constant force, not subject to disturbances by expansion and contraction, as is the case when the adjustment is made by metallic connections.

It should be observed that the setscrew may have a rubber point to support the adjustable plane, in order to prevent short-circuiting when the screw is fitted in metallic supports. Furthermore, I desire it to be understood that the screw is not the only device which can be used for adjusting the inclined plane. I may use any other suitable device for varying the inclination of the plane which supports the loose electrodes.

I am aware that a loose gravitating electrode has heretofore been fitted on a fixed inclined plane of a telephonic transmitter, and

that an instrument of French origin has a glass tube secured to a telephone mouth-piece and connected with a jointed tubular standto set the tube at different angles. In such instrument the glass tube contains a series of carbon balls or spherical electrodes which cooperate with an electrode carried by the diaphragm.

My instrument differs from the above, since I use a stationary support or holder for the diaphragm and a level or flat plane supporting a single loose electrode and pivotally connectedwiththe diaphragm support or holder to set said plane at any desired angle in relation to the diaphragm-support.

What I claim is 1. In a telephonic transmitter,the combination, with the fixed supporting-frame and the diaphragm and its electrode carried thereby, of a platform pivotally connected with the fixed supporting-frame, theloose sliding gravitating electrode resting upon said pivoted platform and making contact with the diaupon the free end of the pivoted platform for I supporting the latter atdifferent angles in relation to the diaphragm, for the object herein stated.

In testimony-whereof I have affixed my sigo nature in presence of two witnesses.

WILLIAM BURNLEY.

Witnesses:

G. A. HAMPsoN, I. T. BEEOHER. 

